Tearing as a test for mechanical characterization of thin adhesive films

Abstract

Thin adhesive films have become increasingly important in applications involving packaging, coating or for advertising. Once a film is adhered to a substrate, flaps can be detached by tearing and peeling, but they narrow and collapse in pointy shapes. Similar geometries are observed when peeling ultrathin films grown or deposited on a solid substrate, or skinning the natural protective cover of a ripe fruit. Here, we show that the detached flaps have perfect triangular shapes with a well-defined vertex angle; this is a signature of the conversion of bending energy into surface energy of fracture and adhesion. In particular, this triangular shape of the tear encodes the mechanical parameters related to these three forms of energy and could form the basis of a quantitative assay for the mechanical characterization of thin adhesive films, nanofilms deposited on substrates or fruit skin.

Tearing of thin sheets: Cracks interacting through an elastic ridge

“…This system has already been studied when the sheet adheres to a flat substrate. In this case, the balance between fracture, adhesion, and bending energies yields to converging * fabian.brau@ulb.ac.be linear crack paths [37]. This system has been used to study mechanical properties of graphene [38] and to show that the curvature of the substrate modifies the crack paths, leading even to diverging trajectories [39].…”

“…[37] and by analyzing the elastic energy of the film essentially contained in the ridge joining the two cracks. We find that both elastic and fracture energies determine the crack paths.…”

90° Peel off Tests of Tissue Engineered Osteochondral Constructs: A New Method to Determine the Osteochondral Integration

“…There are published international standards for peel tests (ASTM, West Conshohocken, Pennsylvania, USA) which determine the method of test execution for different industrial materials. ASTM D 3330 was the starting point for the tests developed and used here [5]. Until now there have been two published papers which analysed with a -peel test the mechanical quality of the cartilage-cartilage bond for specially prepared articular cartilage specimens.…”

“…Peel tests are a standard method in industry for evaluating bonding of adhesive materials to surfaces, but they are not a common method in medicine or biology [5]. Peel tests record force during the course of the peeling process, usually conducted at a constant speed.…”

Graphene as a Prototypical Model for Two-Dimensional Continuous Mechanics

“…At the same time, the width of the peeled-off ribbons gets narrower until they reduce to nothing. The tapering angle predicted by continuum elasticity [45]-extrapolated to graphene in the case of low adhesion-is governed by the equation [35] sin…”